Add PartialCallabte::partial()

Author: zonuexe

src/Functools/PartialCallable.php

@@ -31,6 +31,16 @@ public function __invoke()
         return call_user_func_array($this->callable, $this->arguments(func_get_args()));
     }
 
+    /**
+     * Make partially applied function
+     *
+     * @note Returns new instance
+     */
+    public function partial(array $arguments)
+    {
+        return new PartialCallable($this->callable, $this->arguments + $arguments, $this->pos);
+    }
+
     private function arguments(array $additional_arguments)
     {
         $arguments = $this->arguments;

tests/Functools/PartialCallableTest.php

@@ -3,6 +3,17 @@
 
 final class PartialCallableTest extends \PHPUnit_Framework_TestCase
 {
+    public function test_partial()
+    {
+        $func = function ($a, $b, $c) { return $a.$b.$c; };
+        $p1 = new PartialCallable($func, [2 => "c"], 1);
+
+        $p2 = $p1->partial([0 => "A"]);
+        $this->assertInstanceOf('Teto\Functools\PartialCallable', $p2);
+
+        $this->assertEquals("ABc", $p2("B"));
+    }
+
     /**
      * @dataProvider dataProviderFor_array_map
      */